On the catalytic activation of water-soluble NHC-Au(I) complexes by sonication and microwave irradiation: A comparative assessment

Abstract Within the realm of sustainable chemistry and increasing demand for eco-compatible methods, this article describes our attempts to activate some water-soluble N-heterocyclic carbene (NHC)-based gold(I) complexes under two well-known and safe irradiation protocols: microwaves (MW) and ultrasound (US). A textbook reaction, alkyne hydration, was chosen to assess the performance of such activation protocols and their influence on the catalyst's ability to drive the reaction to completion. Reactions can easily be conducted in pure water or aqueous methanol (1:1). We show that sonication significantly enhances this transformation affording the product in higher yields and shorter reaction times than non-assisted reactions in water, while MW energy gives the desire product in quantitative yield in water:methanol after just 1 min.